Native to Bolivia and Argentina, this small cactus cultivar is a study in contrasts. The plant itself is compact and unpretentious, a dark green globe two to three inches tall studded with woolly white areoles. Then summer arrives, and it opens blooms that are disproportionately large and deeply fragrant, pure white flowers that cover the plant entirely for their brief, single-day lifespan before closing again. The plant repeats this performance two to four times through the season.

Growing it is straightforward. A clay pot with several drainage holes, a gritty cactus or succulent mix, and a position in full to partial sun are the fundamentals. Allow the soil to dry completely between waterings, and keep the plant above freezing through winter. It is reliably hardy only in zones 9 to 11. Mealybugs, spider mites, and scale insects are the occasional threats; overwatering in high humidity remains the most common cause of failure.